


Exchange Problems

by LilLovelyanime



Series: KHR Rarepair event 2019 [2]
Category: Katekyou Hitman Reborn!, モンスター娘のいる日常 | Monster Musume no Iru Nichijou
Genre: Accidents, Alternate Universe, Care of Magical Creatures, Clumsiness, Crossovers & Fandom Fusions, M/M, OOC, Out of Character, What type of monster should the other Arcobaleno be?
Language: English
Status: In-Progress
Published: 2019-07-14
Updated: 2019-07-14
Packaged: 2020-06-28 06:28:33
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,649
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/19806595
Author URL: https://archiveofourown.org/users/LilLovelyanime/pseuds/LilLovelyanime
Summary: Having the house to himself for the next few months, Tsuna intends to spend his time playing video games and reading manga. That is until some strange man knocks at the door informing him that he has been chosen as a Host Family for the Cultural Exchange Program. Now he finds himself responsible for another living person. KHR Rarepair Event 2019, Cloud Day: crossover and fusion.





	Exchange Problems

**Author's Note:**

> Disclaimer: I do not own KHR or Monster Musume. I write this fic to practice writing and for my own amusement. I do not make a profit from this fic.

With music playing in the background, a young man with messy brown hair is on his hands and knees in the kitchen. A bucket of soapy water rests next to him and in his hand he holds a scrub brush as he furiously tries to clean the stubborn stain stuck to the white tile floor. Brown eyes flashing orange as he scowls and mutters under his breath in irritation.

Gritting his teeth he stands up and throws the brush into the bucket, causing the soapy water to splash onto the floor. Sick of, unsuccessfully, cleaning the floor he takes a few steps away with the intention of making himself something to eat but as he puts his foot down he slips, on the aforementioned soapy water, and falls landing on his back with a loud crashing sound.

Looking up at the ceiling, Tsunayoshi Sawada thinks, 'and this is my life. One mistake, mishap and failure after another.'

While some may take the young mans thoughts as being overly dramatic, the truth is that Tsuna is a hopeless case. At twenty-four, he has no friends, no love interest, is accident prone and is generally considered a total mess. He has never held down a job for longer than three days, still lives at home and is dependent of his parents. Attending college has been impossible because his grades had been abysmal. Even doing chores around the house usually end in bodily harm. In other words Tsuna is a completely hopeless young man with no goals or plans. The only good thing about him is that over the years he has gained a decent looking face and years of running away from bullies has given him the body of a runner.

Slowly getting up he winces in pain and rolls his shoulders to make sure everything is working properly. For a moment he looks to the mess on the floor and considers cleaning it up. On one hand, it is a potential hazard and knowing his luck it is very likely he will slip on it agian. Though, on the other hand, Tsuna is tired, lazy and just wants to finish playing that new video game he recently purchased. After internally debating it, he comes to the conclusion that his video games are more important then a little mess he can clean up later. Besides it's not as if he needs to worry about his mother complaining about him being lazy or leaving messes about the house. Usually he would but thankfully, his mother isn't home and she's not due back for another four months. This means, currently Tsuna is living by himself.

The reason his mother is gone and he is living by himself is due to his father, Iemitsu Sawada. Throughout his childhood his father was only home a handful of times as he was too busy with work. Then out of the blue, a little over a week ago, he had barged into the house declaring that he and Tsuna's mother would be going on a four month long cruise around the world, as some kind of second honeymoon. His mother had been delighted, so there hadn't been much he could say about it. All in all, he is just thankful that his parents aren't kicking him out and just expect him to take care of the house while they're gone.

Leaving the kitchen and mess behind him, Tsuna enters the living room and hears someone talking. Looking over to the sound, he sees that the television is on and some sort of news program is playing.

'I must have left it on,' he thinks to himself as he approaches the T.V. and hears some of the topics being discussed.

"The Cultural Exchange Between Species Bill, was passed three years ago, even so humans and non-human liminal species also known as extra-species are remaining mostly seperate. Without the two groups interacting with each other how can they co-exist with each other?" A male voice asks.

"That's a great question. The whole point of the Bill is to allow for both groups to slowly get to know each other," a feminine voice explains. "By slowly intergrating, both sides can get used to any physical and cultural differenses."

"That maybe, but some are claiming that the real reason why it is taking so long is due to incidents between human and extra-species. There are even rumors that humans have been hurt while interacting with their homestay."

"Thats.." Turning off the T.V. Tsuna cuts off whatever the woman is about to say and rolls his eyes at the topic. About three years ago the governments of the world came forward with the news that creatures from myths and fables are real. That they have been living separately from humans and both groups have decided that all species can benefit from open and peaceful co-existence with each other. But due to fear, anxiety, disbelief and distrust, it was also decided that humans and extra-species would slowly be introduced to each other. The cultural exchange program act, is how the government's intends to introduce the species to each other. Supposedly the whole thing operates in the same manner as a typical cultural exchange program. But none of that involves Tsuna, there's no way such a small town like Namimori would be chosen to host an extra-species. That only happens in big cities like Toyko.

Walking away from the television Tsuna can't help but think, 'though, it certainly would be interesting to meet one, they're said to look like creature from mythology.'

Images of elves, fairies and angels whirl around in his head as he walks to the stairs. Just as he is stepping down onto the first step the doorbell rings. Awaken from his day dreams, he turns to look at the door. Looking down to the state of his messy white short sleeve shirt and old blue jeans, his first thought is to ignore them and hope they go away. This isn't an option as the doorbell is rung again and again. Feeling irritated, Tsuna walks up to the door and tugs it open. Glaring up at the tall white haired man in front of him, in a rare moment Tsuna considers giving the man a piece of his mind but holds back as the man cheerfully talks to him.

"Hello, good morning! I hope your day has been enjoyable!"

"Eh, yeah?" Tsuna says a bit thrown off by the mans emthuism.

"My name is Mr. Kawahira, a Coordinator for the Cultural Exchange Program! In particular I am your coordinator." He says and pulls out several books from nowhere and shoves them at Tsuna. "These are the required manuals, rules, regulations and info booklets needed to assure that you understand everything that needs to be known about your homestay and rules on your part."

"Wait, what?" Tsuna asks not understanding what is going on.

"Let me be the first to thank you for agreeing to be a Volunteer Host Family," Kawahira says as he grabs Tsuna hands causing him to drop the books he'd been holding.

"I think there's been a bit of a misunderstanding, I'm not..." he tries to interrupt.

"No need to be so shy," Kawahira says as he takes a step back and points behind where a person with short purple hair can be seen sitting in a wheel chair. "Really, thank you so much! I know that you weren't originally chosen to be a host family but an incident occurred with Skull's original host family, so we really appreciate you being one of our backups."

"Skull, incident?" Tsuna mutters looking at Kawahira.

"Wait! Is this that Interspecies Homestay Program?" Tsuna asks in surprise, "but I..." He begins to refuse the man because he has no idea whats going on, he never heard anything about being a host family in the program and there is no way he can take care of a extra-species. He wasn't even allowed to have a pet. It's then that his eyes wander to the person in the wheel chair, who must be the 'homestay' and he takes notice of their button down long sleeve black shirt, the long purple skirt that hides everything from the waist down, the tattoos on their face and the solemn look they wear.

'An inccident, huh?' Tsuna thinks not liking what that implies.

In truth, he really doesn't want to be responsible for someone else. The only living creature he's ever been responsible for in his life where a pair of goldfish, which passed away in less than twenty-four hours in his care. But looking at the girl, Tsuna finds that he can't just turn her away.

"So..." Tsuna says as he accepts his fate, "what do I have to do?"

"As the Host family, all you have to do is respect your homestays cultural rituals or habits, treat and include them in your families routines and customes. Supply food that meets their nutritional needs and any necessary personal items. You also need to make sure your home is compatible with your homestays physical and mental needs." Kawahira explains and goes on to say, "Skull is an aquatic extra-species so you'll most likely need a pool."

"A pool?!" Tsuna asks in shock and horror as he thinks about how much that will cost and how long it will take to build.

"No need to worry. The government will reimburse you!" He says, "also since these are extenuating circumstances we'll be sending some professionals to fix up the house tomorrow. They'll take care of the pool and any other small changes that need to be made. The forms for reimbursement can be found in that book right there."

Tsuna stares down to the mess of books at his feet and looks up to ask more question but is shocked to see Kawahira is almost out of sight as he runs away. He can only make out a few words, "Sorry but I'm needed else where," before the man is out of sight.

Turning to look at Skull, Tsuna feels a chill down his spine as he realizes he's now in charge of a living person. A living person who is basically a diplomatic representative for her species.

'What have I done!' Tsuna thinks as he begins to pick up the books on the ground. 'This isn't going to work out! I should just call someone and explain that I cant do it. Wait, Do I even have a number for these guys!? Maybe I can find one online?'

Deep in thought, Tsuna accepts the book being handed to him and says, "Thank you."

He then realizes that someone passed him that book and looks up to find the extra-species looking down at him. Meeting her purple eyes, Tsuna flushes in embarrassment and stands up, almost tripping over his own feet in the process.

Balancing himself, he says, "um, this is a little sudden, so I don't think that our house has all the accommodations that you're accustomed to. But, Mr. Kawahira did say that someone will be coming by tomorrow to fix things up. So please bear with it for now..."

Looking at her he says, "Kawahira said something about you being an aquatic type. The bath is pretty big so maybe you can use that for now?"

Tsuna has no idea what it means that she is an aquatic type. He can only assume that means she needs a source of water.

Though thinking about the wheelchair she is using, he wonders, 'does that mean she has a tail? A fishes tail? Is she a mermaid?!'

"I like saltwater," is the mumbled reply.

"Eh! Salt water!?" Tsuna says now starting to panic

"But I should be fine until tomorrow," She says.

"Maybe if I bought the stuff they use for salt water fish tanks," Tsuna mutters as he walks into the house and looks at the stairs leading to upstairs, he comes to a sudden realization. 'The bath is upstairs, that will make it difficult for her to go up with her wheelchair...wheelchair... eh! That's right, she's in a wheelchair! I need to help her over the step and into the house!'

Spinning around in a panic, Tsuna sees that Skull is already in the house.

"What is it?" Skull demands startled by Tsuna sudden movement and his panic stricken face.

"Oh, it's just that...I thought you may have needed some help into the house. What with your wheel chair."

"I'm perfectly capable of getting around by myself," Skull pouts.

"I see," not quite understanding how that is possible but not wanting to ask any questions that may upset his guest he decides to ignore it.

Placing the books on a table he notices the time and realizes that if he wants to get home in time for dinner, he'll have to leave pretty soon for the pet store. With the thought of dinner, Tsuna wonders if he even has anything that Skull can eat.

Walking towards the kitchen Tsuna asks, "Skull what do you usually eat? Also, are there things you can't eat or will make you sick."

"I don't think there's is any type of food I can't have but I prefer seafood like crabs, fish, shrimp, mussels, eel and octopus."

"I see, so if i make a fish dish with some veggies and rice that will be fine."

"Yeah," Skull confirms.

"In that case, I'll stop by the grocery store on the way back from the pet store. Is there anything you need right away," he asks as he heads for the fridge to check its contents.

"Not really," she says.

Turning away from the fridge and taking a step forward, Tsuna finds himself slipping on a wet spot on the floor. Flailing about, he ends reaching out his hand in a desperate movement to catch his fall. At the same time, Skull stands up with the intention to help but misses when trying to catch him. Instead Tsuna falls, his hands getting caught in some fabric on the way down. Face planting on the ground he hears a ripping sound.

Embarrassed that his house guest has seen him being his usual clumsy self he quickly stands up and notices the purple cloth in his hand. Realizing what it is, he starts to panic and unconsciously looks down. Freezing up as he sees a particular sight. Instead of human legs or even the tail of a mermaid, he sees several purple tenticles.

"Oh?" Tsuna says as he looks at Skull. Giving the other a once over he sees that while the top half of Skull looks human, below the hips her pale skin turns purple and instead of legs there are tentacles. Around the hips is a purple cloth that covers any sensitive areas and there is some sort of string or cloth that reaches above the hips that is mostly covered by the cloth, almost looking like the string or cloth of a bikini bottom or speedo.

Normally, any other person would have been disgusted at the sight or at the very startled at what they have seen. As for Tsuna, he simply stares at the unusual appendages and asks, "can I touch them?"

A brief silence and then a shriek of, "what!" Causes Tsuna to look up at the red face of his guest.

Realizing that maybe that was a bit forward or rude, Tsuna flushes and stammers out, "I mean not that way or whatever! It's just, I've never seen anything like that. Are they really tentacles? Is that how you got in the house? Can you pick things up with them?"

Face still red Skull asks with tears starting to form in her eyes, "don't you think they're gross?"

"No," Tsuna honestly answers, "I think they're pretty cool looking!"

"Is that so?" She asks with a smile which quickly morphs into a frowns as she whines, "and here I was worrying that you would be like those people."

"Those people?" He asks in confusion

"My original host family," Skull complains."They all freaked out as soon as they saw my tenticles! It was incredibly rude. Screaming about something called the, 'Little Mermaid' or something. I thought that maybe other humans would act the same way...So I ordered a wheel chair and was using that skirt to hide them."

"Oh, that makes sense," Tsuna says as he thinks, 'that must have been a terrible experience for her. No wonder she wants to hide them.'

"So, they really don't bother you at all?" She asks as she grimaces.

"No."

"In that case," Skull says as she holds up one of tenticles, "then I guess, it's okay if you touch a little bit."

Hand reaching out Tsuna grasps the tentacle and is amazed at its texture, like a combination of soft but firm and velvety but slimy. In the past he remembers helping his mother prepare some octopus, from what he remembers of that it's a similar feeling but different. It's just to hard to explain. In the back of his mind he wonders if they will leave a slime trail on the floor, as that could be a little troublesome cleaning up.

At the sound of a breath being sharply being sucked in, Tsuna looks up and notices Skull red face and feels his own face start to heat up. Realizing that he's being a little too familiar and that is very unlike him, he quickly releases the appendage and takes a step back.

Clearing his throat he then asks, "So you can get around on land with your tenticles, they're like your legs and feet? Are you a type of mermaid or something?

"Basically. And no, I'm a Scylla. Mermaids are a completely different species," Skull says face returning to a more natural color.

"Do you need anything special to walk around on land or anything? Or are you going to dry out without seawater?"

"Not really," Skull replies, "once they put in a pool for me, it will be all good. I actually have some special drinks and pills that will help me stay hydrated when I'm staying long periods on land."

Thinking about it Tsuna says, "I'd still feel more comfortable if I try to get some supplies from the store, just in case. I'm not too sure about the rules on taking you with me to the store or leaving you home alone."

"I'm not a little fry!" Skull shouts out in indignation and then pouts, "I can take care of myself. But the rules say I can't leave the house without a member of my host family being my escort."

"Oh," Tsuna replies as he realizes that, Skulls situation makes her dependent on others. "In that case do you want to go with me to the store? You can help pick something out for dinner."

Blushing Skull says, "I'd like to but wouldn't everyone stare?"

"They'll totally stare," Tsuna admits with a deadpan expression.

"Then should I wear a skirt and use my wheelchair?" A flustered Skull asks not wanting to be seen as some type of freak.

"Is that really nessassary?" Tsuna asks.

"Would you want to be stared at as if you are some kind of freak?!"

"Well, no," Tsuna replies, "but this whole interspecies exchange program is to get you used to human and humans used to you. It's great that you want to blend in but people aren't going to get to know you if you pretend to be someone you aren't."

"You have a point but..."

"Besides, I'll be with you," Tsuna reassures with a smile, "if there's any trouble I'll help you out."

At Tsuna words Skulls face turns bright red and they look away. This goes unnoticed by Tsuna as he has a minor melt down, as he wonders what is wrong with him and how could he say something like that. He is loser Tsuna and if something happens, there is no way he'll be of any help.

"Okay," Skull suddenly says, "I'll go. Just give me a moment. This shirt has been bugging me all day. Just let me take it off."

"Right," Tsuna says then does a double take as he realizes what she said. "Wait!? You're going to take off your shirt?! But... but isn't that indecent."

"Huh," Skull mutters as she struggles with taking off her shirt, "is that some sort of human thing?"

"I mean, I guess your pretty flat chested," he whispers and then shakes his head changing his thoughts, "Wait, no! No matter how flat chested a girl is, it's still indecent to not have something covering your chest!"

Finally ripping the shirt off and throwing it to the floor Skull gives Tsuna a questioning look, "huh, what do you mean by girl?"

With the shirt removed a well chiseled chest is revealed, on either shoulder are intricate tattoos and on the left side of the very male abdomen is a tattoo of a ship.

"Wait, you're not a girl?" Tsuna asks.

"of course I'm not a girl!" Skull responds, "why would you think I'm female?!"

"Well, you know," Tsuna tries to elbrate, "the skirt."

"How does wearing a skirt make you think I'm a girl?"

"Because normally only girls wear them."

"What!? Thats not true!" Skull insists, "I saw plenty of pictures of male humans wearing them!"

'What kind of pictures have you been looking at,' Tsuna thinks.

"Anyway, you said we were going to the store," Skull says as he begins to walk towards the front door, "so let's go."

Tsuna watches him go, eyes drawn to the others tentacles and the way they move. He then processes what the other said and snaps out of it, "Wait a sec! Even for a guy it's not exactly considered decent if you walk around without a shirt."

**Author's Note:**

> For the KHR 2019 rare pair event. This is day 6, cloud day, Crossover/fusion.
> 
> Years ago I watched some of this anime called Monster Musume. I thought it was a little funny until it started to get a little too extreme for me. In the beginning a lot of the more mature jokes went right over my head. It's not a kids or teen anime that's for sure. The only reason I remember it is because I thought it was an interesting idea to have mythological creatures to be revealed and have them introduced into the human population. The worst thing about the series was that all the male mythological creatures are super ugly. So in this fic the guys are super good looking.
> 
> In the beginning Tsuna thought Skull was a girl, thats why he is referred to as a she in the beginning. He did manage to convince Skull to wear a tank top. A large indoor pool was built on the first floor, Tsuna has no idea how it fits in the house. Juvenile octopus are called fry or younglings. Skull is a Cecaelia/ Scylla- half human, half octopus.
> 
> I may continue this, not sure. If I do Tsuna will probably end up as the host family for the other arcobaleno.
> 
> What type of monster do you think the other Arcobaleno would be?


End file.
